Electrical musical instrument



Jan. 23, 1951 M. GRUDIN 2,539,130

ELECTRICAL MUSICAL INSTRUMENT Filed March 4, 1948 4 Shee'tsSheet 1 BY WATTORNEY.

Jan. 23, 1951 M. GRUDIN ,5

ELECTRICAL MUSICAL INSTRUMENT Filed March 4, 194a 4 SheetsSh eet 2INVENTOR.

BY WW ATTORNEYS.

Jan. 23, 1951 M. GRUDIN ELECTRICAL MUSICAL INSTRUMENT 4 Sheets-Sheet 3Filed March 4, 1948 I 1I!I!vrllltlvlllIIIIIIIIIIIIZIII iillll'lllt I IINVENTOR. Mfll/E/CE GKUD/N fioRN EYS.

OUTPUT C OMPEMJ'A T025 Red. Fans.

Jan. 23, 1951 GRUDlN 2,539,130

ELECTRICAL MUSICAL INSTRUMENT Filed March 4, 1948 4 Sheets-Sheet 4ATTORNEYS.

l atenteci jan.

UNITED STATES PATENT OFFICE ELECTRICAL MUSICAL INSTRUMENT MauriceGrudin, Paterson, N. J. Application March 4, 1948, Serial No. 13,028

21 Claims. 1

This invention relates to playable electrical musical instruments, bythe playing of which, musical compositions may be rendered by amusician, and wherein the sounds are produced by electrical phenomena,as distinguished from sounds produced by natural instruments, strings.pipes, reeds or the like.

In broad terms, the invention comprises a playing console, equipped withstops or slabs, and one or more keyboards controlling the initiation andtermination of musical sounds. The sounds are produced by a loudspeaker, and are derived by electromagnetic or electro-optical meansfrom a plurality of sound tracks, tapes or wires, there being a separatetrack for each pitch and timbre within the scope and range of theinstrument. The invention further includes arrangements by which tonesof different pitch and timbre may be registered with each of the severalplaying keys of the instrument, so that each key of the instrument maybe caused to produce the nominal pitch represented thereby, in any oneof several timbres, and also to produce the pitches of tones one or moreoctaves away from the nominal pitch, again in any one of severaltimbres. The invention further provides for the production of aplurality of complex tones simultaneously, with each tone retaining itsinherent fidelity and timbre characteristics.

A general object of the invention is to provide an organ-like instrumenthaving a conventional console, the instrument being substantiallyselfcontained and semi-portable in character, wherein the key manuals,pedals and stops have both an arrangement and scope which Will enable askilled organist to use the instrument Without special training orindoctrination. Thus, the playing technique of the instrument, beinglike that of the more or less conventional organ, enables the player touse the instrument inter changeably with a fixed type of organ. Thisplaying interchangeability greatly facilitates both practice andtraining for ,organists. 'An other object is to provide an instrumentwhose scope is selectively unlimited, and to permit the use of anyappropriate number of independent voices, including conventional organvoices and a large selection of orchestral instrument voices and specialand unconventional voices, if the latter may be desired. A furtherobject is to provide an instrument which keeps each produced tone,'voice or timbre independent, so that whenvarious voices and tones areused coincidentally, each retains its own timbre with complete fidelity,as does a full organ or orchestra. Another object of the invention is toprovide selective registry of different voices and their pitches on thekeyboard, and to provide for selective registration or production ofseveral voices and pitches thereof by depression of a single key of amanual. A further object is to provide for the selective registration ofone or more voices and pitches on several keyboards, one of which maycomprise pedals.

Another object is to provide an instrument in whichtones of desiredtimbre and pitch are pro-'- duced electrically, either by photoelectricor magnetized wire or tape means, the electrical impulses derived fromsuch means being amplified, and converted to sound by a loudspeaker orthe like. Preferably, the instrument is unitary in construction, thespeaker unit being embodied in the instrument, or being separatetherefrom as desired.

A further object of the invention is to provide means for producingsound track or sound wire or tape elements from a single tone of desiredtimbre to embrace a pitch range appropriate to the timbre, for use inthe electrical musical instrument.

It is known that various playable electrical musical instruments havebeen proposed wherein the tones are synthesized from their funda--mentals and harmonics, to produce any timbre desired, either of aconventional instrument, or of an unusual quality which may notordinarily be found in a natural instrument. However, such instrumentshave serious limitations when chords are played or when several octavepitches are registered by the same key, for the fidelity of componenttones of chords is sacrificed due to the coincidence of synthesizedfrequencies in several tones of the chord and the consequent aberrationof the timbre desired. The harmonics of one tone may coincide withfundamentals or harmonics of another, whereby the timbre of both ismaterially modified. Only by compromising the true timbre of tones maypleasing chordal efiects be produced, and these are only tolerable byvirtue of the courtesy or insensitivity of the player or listener.

Further objects of the invention will become apparent in reading theannexed detailed description in connection with the drawings, which showthe essential provisions of the invention in one or more preferredforms. These forms are, however, exemplary, and are not to be construedas limiting the scope of the invention.

In the drawings, in which similar reference numbers indicate similarparts, and in which certain symbols are used for assisting understandingof the invention;

Fig. 1 is a schematic diagram of a portion of a keyboard of oneembodiment of the instrument and associated registry and sound actuatingcircuits;

Fig. 2 is a front elevation of an entire instrument showing the generaldisposition of the components therein;

Fig. 3 is an end elevation of-th-e entire'instrument;

Fig. 4 is a partial schematic diagram of a modification or addition tothe instrument to produce fundamental and harmonic tones;

Fig. 5 is a side sectional elevation of one of the sound track units;

Fig. 6 is an end sectional elevation of the sound track unit of Fig. 5;

Fig. 7 is a general wiring scheme of one embodiment of the instrument;

Fig. 8 is an end elevation of a soundtrack unit utilizingelectromagnetic pickups;

Fig. 9 is a planof a portion of the unit shown in Fig. 8;

Fig. 10 is an enlarged end elevation, partly in section, of one of thepickup units of Fig. 8;

Fig. 11 is a schematic wiring diagram of the circuit system utilizedwith the pickups of Fig. 8;

Fig. 12 is an enlarged end elevation partly in section ofan'alt-ernative electromagnetic pickup unit;

Fig. 13 is a schematic wiring diagram of a circuit system utilized withthe pickup of Fig. 12; and

Fig. 14 is a schematic arrangement of a sound ,transposing machine.

Referring briefly to Figs. 2 and 3, I show an entire instrument in theform of ,an organ console Ill, including a plurality of key manuals 12,a panel for stops or slabs l4, pedals l5, and swell pedal 16. Theconsole contains a plurality of demountable box units [8 each comprisinga voice, such as flute, string, oboe, horn, diapason, etc., all drivenif desired by a common motor 20. The voices may be of any desirednumber, eight being shown as a number suitable, for average needs, toproduce musical effects over a wide range. The voice boxes may beinserted into the ends of the console, leaving the middle part free forincorporating junction panels, amplifiers, speakers, and necessaryauxiliaries which will be described.

Now referring to Fig. l, I show a key manual portion l2, embracing 5octaves, wherein the keys are identified by their pitch symbols C0, C1,C2, etc., some of the intervening keys of each octave being similarlysymbolized. Each key operates a S. P. S. T. switch 2| which is connectedto a contact 22 bearing the key symbol, on a main contact panel 2 1.This panel includes a plurality of horizontally shown contact rows, eachrow comprising contacts for all keys of the keyboard; all contacts onvertical lines are inter-connected with each other and with the keyswitches for the keys having the same key symbols.

Into all contacts of the first contact row 26 may be plugged a bar 28carrying contacts 30, each engaged with one of the contacts 22, theseveral contacts 30 being connected by conductors 32 to the points 33 ofone member of a multi-- point stop switch 34, actuated by a stop buttonor slab constituting one slab of the panel M (Fig. 2). The other memberof the stop switch 34 carries a plurality of points 35, respectivelyconnectible or disconnectible relative to the f rst set of points 33 byoperation of the stop. Conductors lead individually from each point ofthe set 35 to each of a series of solenoid units 38, said solenoid unitsbeing operable to open and close a sound track to a pickup as will bedescribed. The stop 34 when operative, gives nominal registry of thekeys with the solenoid units 38, so that, for instance, depression ofkey 03 produces the pitch C3 by operation of the solenoid unit 38corresponding to pitch C3 of the voice represented by the stop 3 Thisyields 8 foot pitch registry. In addition to nominal key registry, it ishighly desirable to use, at times, registries of one or more octaveshigher or lower than nominal, to give richness of tone and additionalvolume, and also to register high or low tones on the manuals forconvenience in playing the instrument. Also, different voices indifferent parts of the tonal range may be played simultaneously bysingle keys. Provision is made for different registries in the mannerdescribed below.

A contact bar 43 is plugged into the row of contacts 42, on the panel24, the contacts 44 of the bar being connected to fixed contacts 46 of astop switch 48. Movable contacts 50 of the stop switch are connected ,toseparate windings incorporated in the solenoid units 38, but in an ordersuch that, when the stop switch 48 is closed, depression of key C3operates the solenoid unit corresponding to pitch C2, and depression ofany other key will actuate the solenoid unit corresponding to a pitchone octave lower than the nominal key pitch. This yields 16 foot pitchregistry.

A contact bar 54, plugged into a row of contacts 56 on the panel 24,connects said contacts to a stop switch 58, which in turn connects tosolenoid units 38 in an order such that, when the stop 58 is operative,depression of key C3 operates the solenoid unit correspondin to pitchC4, and depression of any other key actuates a solenoid unitcorresponding to a pitch one octave higher than the nominal key pitch.This yields a foot pitch registry.

In the same manner, registries of 32 foot pitch and 2 foot pitc h-thatis, two octaves lower or two octaves higher than nominal, may be securedby providing additional contact bars and stops.

The same contact panel 24 may be utilized, in conjunction withadditional stop switches such as 60, to connect othersets of solenoidunits 38a to the keyboard, such other solenoid units being associatedwith other voices of the instrument. Ofiset tone registries may also beeffected in the manner described to secure fifths, seventeenths, or anyother desired interval from the nominal tone. That is, the playing ofkey C1, for instance, may -prcduce tone G1 (for the fifth) or E3 (forthe seventeenth) with corresponding intervals for other keys.Furthermore, registries may be changed at the discretion of theorganist, by lifting out a bar, such as bar 28, from its contacts 26,and reinserting it into the row of contacts 26 in such relation as toshift the coincidence of contacts 39 and 26 from the original registryto an octave higher or lower, or oifset for fifths, seventeenths,nineteenths or any other desired interval.

The contact panel 24 is associated with a single keyboard or manual l2.If additional manuals or pedals are used, each has a panel, like 24, toenable a plurality of connections to be made to the available voices ofthe instrument. In this connection, the solenoid units such as 38 maynot only be connected to one manual through several stop switches tosecure different octave registries, but may also connect to one or moreadditional manuals or pedals, either for single or multiple octaveregistry with each,

From the preceding description, it is apparent that stops 58, 48, 34 maybe actuated individually or jointly, to secure desired octaveregistrations on the one manual shown.

In Fig. 4, I show a connection arrangement for onevoice of theinstrument to provide a plurality of pure tone qualities over the pitchrange desired, such tones being produced from sound tracks of pure sinewave character without the overtones which characterize usual organor'instrumental timbres. These pure tones are, at times, very useful,either to synthesize tones-of unusual quality, to play by themselves, orto fortify and augment tones of complex composition by superimpositionthereon. The Fig, l ar rangement is shown for exemplary purposes-for twopitches A1 and A2 and enables the combination of any one or all of thefirst six harmonics of the fundamental pitches. In practice, theconnections are carried out for all semitone pitches of the rangedesired. The manual keys as previously described operate key switches 2|connected to the panel 24. Several horizontal rows of contacts in thepanel are reserved for liar-- monic connector bars whose plugs arerespectively connected to stop switches respectively designated HI H2,H3, H4, H5 and H6. These stop switches, when in the active positionrespectively set up the solenoid units of the first to sixth harmonics.The harmonics of the fundamental or first harmonic pitches A1 and A2correspond with other fundamentals in the tempered scale as shown in thetabulation below, and the connections from the harmonic stop switches HIto H6 are made to the solenoid units corresponding to such otherfundamentals, as shown. As previously described, the solenoid units havea separate winding associated with the appropriate sound track for eachconnection from a stop switch, to avoid shadow circuits and cross-talk.

I am aware that in order to produce timbres solely by synthesis ofpartials or harmonics it is more desirable to have available more thansix harmonics in more than one degree of intensity. However, I havefound that for a practical instrument of the type herein described, theuse of the first six partials in but one degree of intensity offers bysynthesis and by alteration of stock stops a more than sufiicient numberof timbres for the production of usable and highly desirable musicaleffects. The addition of harmonies opens up a vast field of tone colors,inasmuch as these harmonics in their numerous combinations create newtimbres, and the addition of one or more harmonics to a stock stop orcombination of stops produces a still greater number of new timbres.Thus, (1) the admixture of 6 harmonics alone, (2) the addition of one ormore harmonics to an individual stop or combination of stops, (3) theuse of one or more independent stops, make available to the player anumber of timbres which may well nigh be described as limitless.

Referring now to Figs. 5 and 6, details of a typical voice unit l8 areshown, in conjunction with a series of associated solenoid units 38. Inone arrangement of the invention, each voice unit l8 comprises acylindrical transparent drum 62 secured for rotation in end bearings 64,and driven at constant speed through a transmission 66 by a motor 68.Within each drum is a light source I8, and suitable provisions may bemade for ventilating and cooling the unit by circulating air through thedrum. Around the drum are secured a plurality of axially spaced soundtracks 12, there being one such track for each pitch over the rangedesired, all tracks preferably representing tones of the same timbre.These sound tracks may represent an organ timbre, an orchestralinstrument timbre, or any other, including the fundamentals andharmonics indigenous to each. There need be no particular phaserelationship between the waves of each track, and each track producesits own monotonef of full fidelity and timbre. I have found little or noneed for matching wave patterns at the ends of each track at it iswrapped around and secured to the drum, as the interruption caused bymismatched wave patterns, at the one point in the drum circumference,where the track ends meet, is so minute as not to be noticeable even tothe most critical ear.

Around the drum 62 is disposed a light shield 14 having a longitudinalnarrow slit 16 therealong, or a plurality of holes one opposite eachtrack. Either above or below the shield 14 may be disposed a pluralityof individual tapered light filters 18, one for each track, to enableadjustment of the sound level produced by each track.- Either anotherlong tapered filter may,

be introduced to adjust the sound level of the entire unit, or thefilters 18 could be adjustable jointly, as well as individually, toattain the same result. Spaced beyond the slit and filter is a shutter88 for each track 12, the shutter normally masking the slit and beingmovable to uncover the slit by the associated solenoid unit 38 of whichthe shutter is a part. Beyond the shutters are a plurality of lenses 82for focusing the beams from open sound tracks onto one of a set ofinterconnected photocells 84. These receive light signals from the lamp(0 within the drum as modulated by the sound track 12.

Photocell output is conducted to an amplifier 88 (Fig. 7), and amplifieroutput controlled as to overall sound level by the swell pedal I6, istransmitted to a speaker 90.

Accordingly as one or more shutters 8!! are operated, one or more trueindividual tones are produced in the speaker,,blending to produceharmonious music without distortion or aberration.

The solenoid units 38 (Fig.5) each comprise a plurality of solenoidwindings 92, and an armature 94, carrying the shutter 80, which isoperable by the energization of any one winding 92. One end of eachwinding 92 connects to a common ground, while the other end connects toone contact of one of the stop switches such as 34, 48 and 58 (Fig. 1).This arrangement of multiple solenoids in each unit 38 has been found togive excellent results, and to avoid any possiassarso' bility of shadowcircuits or cross-talk between different stops, keys, and voice units.Other interconnecting arrangements. are no doubt feasible, and I do notnecessarily wish to confine the scope of the invention to the connectionsystion shown. In the solenoid units 38, windings from one to seven ormore may be employed. If but a single tone registry on a single manualis needed, the single winding is adequate. Seven windings are desirablewhen the tone is to be producible in one registry on the pedals and inthree registries (4', 8 and I 6') on each of two manuals.

As noted in Fig. '7, a common power supply may energize the amplifier80, motor 58 and key system, the latter preferably operating at low D.C. voltage through a transformer 90 and a rectifier Bl.

It is contemplated that selective tremolo .effects may be produced byperiodically raising and lowering the overall sound frequencies. Thereare known methods for producing the tremolo, such as by varying thespeed of the motor 08 at cyclic intervals of 5 to 9 per second. Anotherarrangement is to insert a selectively operable cyclically varying drivebetween the motor 60 and the drums 52.

An alternative sound track system is shown in Figs. 8 to 13, wherein aninsulating or nonmagnetic drum I64 is driven, as before, by the motor 08and transmission 68. Preferably, the peripheral speed of the drum is ofthe order of 120 to 250 feet per minute to attain high fidelity soundproduction. Around the drum are secured a plurality of magnetic wires ortapes I06, one for each tone over the range desired, each Wire or tapebeing magnetized to produce, when associated with a pickup and speakersystem, a tone of desired pitch and timbre. The several wires or tapesprovide the desired range of pitch. The wires or tapes are spaced apartto avoid cross-talk, and with each wire or tape is associated one ormore magnetic pickups I08 which are analogous in function to thesolenoid units 38 of the electro-optical system previously described.The pickup comprises pole pieces I01 having a winding Hi9, whose endslead to an amplifier and speaker system.

The Wire-carrying drum I04 is rotated in bearings I I0, and at each endof the drum is a spider H2 having a plurality of spoke-like arms; Htacross the ends of which are secured members H6 upon which the pickupsI08 are mounted. The spiders IE2 are selectively oscillatable about thecenter of the drum, at a frequency of between 5 to 9 cycles per second,while the drum is rotating at constant speed, to attain tremulanteffects. Such oscillation may be attained by a small motor I I8 having acrank I I 9 connected to one end of a spider arm I I4 by a connectin rodI20. When the drum oscillates the frequency of impulses picked up by thedevices I08 varies slightly and cyclically, to yield the tremolo.

Referring to Figs. 10 and 11, based on the general arrangement of Figs.8 and 9, I show one arrangement and circuit system for using themagnetic pickups. The pickup I00 is mounted on a bar I22 pivoted at I26to one of the members I IS. A light spring I26 holds the bar I22 inplace, and urges the poles of the pickup Ida into light, continuousengagement with the magnetized sound wire I06. The pickup pole piecesand the Wire are preferably highly polished to minimize wear anddistortion of the impulses picked up from the Wire (or tape). Fig. 11shows a fragmentary typical circuit diagram, wherein two keys and twopickups are showns. It will be apparent that an entire key system willbe arranged in generally the same fashion. Each pickup coil I09 connectsto a transformer primary I26 at all times, the two primaries beingrelated to a joint secondary I28. The secondary provides the input tothe amplifier 88 and speaker 90. One end of each pick.- up is,groundedthe other end of each leadingto center points I30 of a stopswitch I32. When the stop switch is off or up, as shown, the pickups areshort-circuited through ground as at I34 whereby they do not transferenergy to the trans.- former I26-I28. When the stop switch is on, thepickup coil ends are connected to points. I35, through the junctionpanel 24 of normally closed grounded key switches I38. When the key.isat rest, the pickup coil I09 is ground-shorted, but when the key ispressed, the short is broken'and the pickup coil I09 ,feeds energy tothe transformer and sound system.

In an alternative system shown in Figs. 1 2 and;

her I I6, serves when energized to move the pick-,

up into contact or pickup relationship to the wire I06, the arm M0having secured thereto an armature I48 entering the solenoid. Cushioningmeans, such as felt, is provided to prevent bouncing of the pickup onthe wire when the solenoid is energized, and additional cushioning meansmay be applied to prevent pickup bounce when it is disengaged from thewire. The solenoids I06 operate in the same kind of key system as isshown in Fig. 1, and are comparable to the solenoid units 38. The keyswitches 2|, junction panel 24, and stop switches are similar. In thisarrangement the pickup coils I09 are constantly connected to theirrespective transformer pri.-. maries I26, but the solenoid circuits arenormally open.

To enable relativel close spacing of wires I06 on the drum I04, and toprovide for an adequate number of pickups I08, the latter may be spacedcircumferentially around the drum as shown in Figs. 8 and 9. By thisarrangement a plurality of pickups may be associated with each wire I06,each pickup being connected to one of the several stop switches toenable playing of a single tone from a plurality of manuals, pedals andkey positions. The pattern for the multiple playing of a single notefollows, in general, the same principles as were outlined heretofore inconnection with the sound-track optical system.

The magnetized wire system shown may yield augmented musical effects,since a specific pitch and timbre may be produced by several pickupseach operated by a different key, the sound pro,- duced by each keydepression being additive to the similar sounds produced by other keydepressions. This has the same effect as though there were duplicated,triplicated or multiplied voices in the organ system. This is desirablebut usually impractical in the natural organ or electrical organanalogue.

In the foregoing description I have used the terms solenoid, andsolenoid units, to designate,-

mane to the invention herein disclosed, there bee I ing many desirablemechanical arrangements ofparts .to fulfill the function required. Ifind that the generalarrangements shown minimize the possibility of keyclick in the speaker system of the instrument, since the pickups orphotocells are always connected during playing, and are rendered activeby optical or mechanical connection to the sound tracks or wires. Werethe photocell or pickup circuits to be made and broken each time a noteis played, obnoxious key click would be almost inevitable.

Further, in either the optical or magnetic pickup systems describedtones are initiated or terminated smoothly, without obiectionablesuddenness. If desired, the speed of tone initiation and termination maybe varied by varying the response speeds of the solenoid units. In themag-' netic wire systems, I prefer to use a sequence of wires on eachdrum which will minimize the possibility of discordant cross-talkthatis, pickup of dissonant frequencies by a pickup unit from wires whichare neighbors of the wire with which the unit is directly associated. Tothis end, all of the C pitch wires are neighbors, and comprise the firstgroup.. The next group comprises all the G pitch wires, then insequence, groups of D, A, E, B, Ft, Ct, Gt, DII, AII, F are arranged.The intervals between all groups are fifths, and the intervals betweenwires in a group, octaves, so that any cross-talk which may occur willalways be harmonious.

The sound wire on the drums (tape being considered equivalent to wire)may be wound as a plurality of separate spaced turns, or the wire may bewound continuouslyto form a multi-turn helix. In the latter form, thehelix turns may be offset sharply from one turn to the next to enableeach wire to run predominantly centrally under its pickups. Themagnetization of the wires to represent appropriate pitches and timbresmay be accomplished before or after the wire is placed upon the drum.

It will be noted that in the optical system, a single light gate may beoperated by any one of several solenoids associated therewith to. securepickup from a single sound track, while in the electromagnetic system, aseparate pickup is preferred for each key and stop combination with theresult that there are several pickups associated with each sound wire.The wire or tape system comprehends their assembly as voice units suchas I6, as previously described in connection with the optical system,all voices being energized by the same drive motor, and all sound beinreproduced by the same amplifier and speaker, with coincidental volumeregulation by the swell pedal I6.

For the purpose of securing true pitch sound tracks either astranslucent tracks for use with the electro-optical system ofreproduction or withthe electromagnetic tape "or wire system, I havevolved a mechanism which may produce an entire range of pitches ofcertain timbre from a recording of asingle pitch of the desired timbre.This mechanism is shown in Fig. 14. It comprises a turntable I60 bornein a housing I62 by a shaft I64, the shaft having a bevel gear I66meshed with a bevel gear I68 whose shaft I is also borne in the housing.The shaft carries a wheel I12 faced with friction material, the wheelbeing engageable with any one-of a plurality of pulley faces on astepped pulley I14. 1 The housing I62 is mounted for tilt and sliding ona horizontal rod I16 carried by brackets I I8, so that the housing, withits turntable and drive mechanism, may be shifted along the pulley 14.The brackets I18 and the shaft I-16are-spaced-fr0m the pulley I14, lyingbehind the pulley and the axis of the turntable I84. Thereby, the entirehousing I62 may be tilted up and down on the shaft I16 as it is slidtherealong, to allow engagement of the friction wheel I12 with any oneof the steps on the pulley. The weight of the housing and its associatedparts is sufficient to load the wheelIIZ into firm frictional drivingengagement with the pulley I14.

The pulley I74 is driven through a changespeed gearset I from a constantspeed motor I82, successive ratios of the gearset having2z1relationship. That is, the pulley I "I4 may be driven at, say, a minimumspeed of 25 R. P. M. Successive ratio steps would be 50, 100, 200, 400and 800. The 13 steps of the pulleyincrease progressively in diameter bythe ratio 1.05946 driving the turntable at similar R. P. M. ratioincrements. For example if the smallest pulley face is .500 inch indiameter successive faces will have diameters .5297, .5612, .5946,.6299, .6674, .7071, .7492, .7937, .8409, .-8909, .9439, and (13)1.0000. If a monotone record I84 of desired timbre is placed on theturntable, and the pickup I86 is connected to a suitable reproducer, anydesired range of all notes of several octaves of the tem-.- pered scalemay be reproduced by changing the driven speed ofv the turntable, byshifting the wheel on the step pulley I14 for semitone intervals Withinan octave, and by shifting the gearset I80 for octave intervals. Theoutput of the pickup I86 is connected to known apparatus to produceoptical sound tracks (12 in Fig. 6) or magnetized sound wires or tapes(I06 in Figs. 8- 12). Such tracks may be produced for use on the drumsforming parts of the voice units I8 of Figs. 2 and 3. Any appropriatetone timbre may be secured by the use of appropriate monotone recordsI84.

Though several embodiments illustrating the invention have been shownand described, it is to be understood that the invention may be appliedin other and various forms. Changes may be made in the arrangements,without departing from the spirit, of the invention. Reference should behad to the appended claims for definitions of the limits of theinvention.

What is claimed is:

1. In an electrical musical instrument, a plurality of sound trackshaving the same and complex timbre and dififerent pitch, at least onepickup energizable by the tracks, a sound producer responsive to pickupenergization, means to translate the tracks relative to the pickup,selectively operable means associated with each track to place the trackin energizing relationship to the pickup and to place the track ininoperative relation to the pickup, a keyboard, a key switch for eachkey of the keyboard, and means to connect eachkey switch to one and moreof said selectively operable means, whereby key switch operation mayplac one and more tracks of the same timbre but of different pitch inoperative relation with said pickup.

2. In an electrical musical instrument, a plurality of sound trackshaving the same and complex timbre and different. pitch, at least onepickup energizable by the tracks, a sound pro-1 ducer responsivetopickup energization, means to translate the tracks relative to thepickup, selectively operable means associated withseach track to, acethe track in energizing relation and to place the track in inoperato thepickup, a keyboard, a key switch-foreachkey of thekeyboard, meansto.

connect each key switch to one and more of said selectively operablemeans, whereby key switch operation may place one and more tracks of thesame timbre but of different pitch in operative relation with saidpickup, said sound tracks comprising filaments magnetized in accordancewith pitch and timbre of the tone to be produced, and said pickupcomprising means magnetically engageable with said filament andproducing electrical impulses in conformance with the magnetization ofsaid filament.

3. An electrical musical instrument compris ing a plurality ofselectively operable key switches each closable toproduce a nominaltone, a plurality of multi-point stop switches each including two setsof points, connections from said key switches to respective points ofone set of each of said stop switches, a plurality of actuators,connections from said other sets of stop switch points to said actuatorsin a plurality of combinations, a full-timbred sound track operativelyassociated with each actuator, and sound produc ing means responsive toenargization of said actuators individually and in groups to produce thesame ful1-timbred sound corresponding to the one or more tracks broughtinto operation by onergization of respective actuators.

4. An electrical musical instrument comprising a plurality ofselectively operable key switches each closable to produce a nominaltone, a plurality of multi-point stop switches each including' two setsof points, connections from said key switches to respective points ofone set of each of saidstop switches, a plurality of actuators,connections from said other sets of stop switch points to said actuatorsin a plurality of combinations, a full-timbred sound track operativelyassociated with each actuator, and sound producing means responsiv toenergization of said actuators individually and in groups to produce thesame character of full-timbred sound corresponding to the one or moretracks brought into operation by energization of respective actuators,said actuators comprising electro-magnetically operated devices operableto render said tracks activeand inactive.

5. An electrical musical instrument compris ing a plurality ofselectively operable key switches each closable to produce a nominaltone, a plurality of multi-point stop switches each including two setsof points, connections from said key switches to respectivepoints of oneset of each ofsaid stop switches, a. plurality of magnetic pickups,actuating means to render said pickups acthe connections from said othersets of stop switch points to said actuating means in a plurality ofcombinations, a full-timbred sound track operatively associated witheach pickup, and sound producing means responsive to energizationof'said' pickups individually and in groups to produce the samecharacter of full-timbred sound corresponding to the one or more tracksbrought into operation by energization of respective actuators, saidactuators comprising electro-magnetically operated devices operable torender said tracks active and inactive relativeto their pickups, andsaid tracks comprising, magnetized filaments.

6. In an electrical musical instrument, a light modulating sound. track,a light source, a photocell responsive'to light from, the source asmodulated' by the track, a light shutter in the path of light from said.source tosaid photocell selectively operable to pass and not to passsaid light, said shutter comprising a movable; shutter else:

I2 ment, a plurality of solenoids individually and, jointly energizableto move said shutter, a plurality of playing key switches connected withand selectively closable to energize respective: shutter solenoids, andstop switching means, selectively operable, and interposed in theconnections from said key switches to said shutter solenoids.

'7. In an electrical musical instrument, a plurality of signal producingunits each comprising a series of tracks having characteristics of Sim--ilar complex timbre over a certain pitch range, a sound producerresponsive tothe signals of the several producing units, a plurality ofplayingkey switches, and means selectively operable to con-' nect eachkey switch to one and more of said producing units simultaneously, inoctave intervals, to produce sound signals from said tracks and soundproducer upon key switch closure.

8. In an electrical musical instrument, a plurality of signal producingunits each comprising a series of tracks having characteristics ofsimilar complex timbre over a certain, pitch range, a sound producerresponsive to the signals of the several producing units, a plurality ofplayingkey switches, and means selectively operable to con,- nect eachkey switch to one and more of said producing units simultaneously inoctave intervals, to produce sound signals from, said tracks and soundproducer upon key switch closure, said selectively operablemeans'including connections to afford a plurality ofv octave registriesof" said key switches with the sound tracks. of said units.

9. For use in preparing a plurality of sound tracks of similar timbrefor an electrical musical, instrument, a turntable for a record of amonotone of desired timbre, a record pickup, sound track recordingmeans'responsive to said pickup, a drive shaft, and a transmission fromsaid drive shaft to said turntable comprising a stepped drum having aplurality of steps having a diameter increment ratio of substantially1.65946 driven by said drive shaft, a follower wheel selectivelyengageable with the drum steps,

and means for driving the turntable fromv the follower wheel.

10. For use in preparing aplurality of sound tracks of similar timbrefor an electrical musical instrument, a turntable for a record of amonotone of desired timbre, a record pickup, sound track recording meansresponsive to said pickup, a drive shaft, a transmission from said driveshaft to said turntable comprising a stepped drum having a plurality ofsteps having a diameter increment ratio of substantially 1.05946 drivenby said drive shaft, a follower wheel selectively engageable with thedrum steps, means for driving the turntable from the follower wheel, andmeans for changing the speed of said drive shaft in the ratio 2:1.

11. For use in preparing a plurality of sound tracks of similar timbreand difierent pitch, for an electrical musical instrument, a record ofmonotone pitch and desired timbre, pickup means for. saidrecord, meanstore-record sound tracks v stantially 1.05946 between steps of increasingdiameter, said wheel and drum comprising input and output members,notnecessarily respectively, means to drive-said input member atconstant 13 speed, and means to drive said single pitch record from saidoutput member.

12. In an electrical musical instrument, a plurality of playing keyseach including a switch, a plurality of full-timbred voice units, eachunit having a range of full-timbred tones of the same voice, a contactpanel having a plurality of lines of contacts, means connecting eachline with a key switch, each voice unit having a plurality of controlconductors each representing one note of its voice unit, and meansoperable to connect the said control conductors from one voice unitsimultaneously and in tonal sequence, to the lines of contacts of saidpanel.

13. In an electrical musical instrument, a plurality of playing keyseach including a switch, a

' plurality of full-timbred voice units, each unit having a range offull-timbred tones of the same voice, a contact panel having a pluralityof lines of contacts, means connecting each line with a key switch, eachvoice unit having a plurality of control conductors each representingone note of its voice unit, means operable to connect the said controlconductors from one voice unit simultaneously and in tonal sequence tothe lines of con-.

tacts of said panel and means to shift said control conductors as a unitto cause registries of said conductors, in tonal sequence, withdifferent lines of contacts of said panel.

14. In an electrical musical instrument, a plurality of playing keyseach including a switch, a plurality of full-timbred voice units, eachunit having a range of full-timbred tones of the same voice, a contactpanel having a plurality of lines of contacts, means connecting eachline with a key switch, each voice unit having a plurality of controlconductors each representing one note of its voice unit, means operableto connect the said control conductors from one voice unitsimultaneously and in tonal sequence, to the lines of contacts of saidpanel and means to shift said control conductors as a unit to causeregistries of said conductors, in tonal sequence, with different linesof contacts of said panel whereby at a players option, registry of a C1key, for example, may be effected with a C0, C1 and C2 tone of any oneof said voice units.

15. In an electrical musical instrument, a plurality of playing keyswitches, a connection panel having a plurality of contact elementsrectilinearly disposed in lines and rows, the elements in each linebeing interconnected and connected to one of said key switcheaaplurality of bars each having a plurality of contact elements engagedwith the panel contact elements of one row, said bars beinginterchangeable between rows and being adjustably shiftable along a row,a plurality of sound signal generating units, one for each bar, eachhaving a range of musical tone signals and each having conductors, onefor each tone, energizable to produce respective signals, selectivelyoperable multiple contact stop switch units, the conductors of saidgenerating units being connected in order to the respective contactsofsaid stop switch units, and means connecting other contacts of said stopswitch units, respectively, to the contact elements of said severalbars.

16. In an electrical musical instrument, a plurality of playing keyswitches, a connection panel having a plurality of contact elementsrectilinearly disposed in lines and rows, the elements in each linebeing interconnected and connected to one of said key switches, aplurality of'bars each having a plurality of contact elements engagedthe panel contact elements of one row, said 14 barsbeing interchangeablebetween rows and being adjustably shiftable along a row, a plurality ofsound signal generating units, one for each bar, each having a range ofmusical tone signals and each having conductors, one for each tone,

energizable to produce respective signals, selectively operable multiplecontact stop switch units, the conductors of said generating units beingconnected in order to the respective contacts of said stop switch units,and means connecting other contacts ,of said stop switch units,respectively, to the contact elements of said several bars, said barsand generatingunits being replaceable, and said bars beingposition-shiftable along the rows of said panel to alter the keyregistration relative to the nominal tones available from saidgenerating units.

17. In an electrical musical instrument, a plurality of playing keyswitches, a connection panel having a plurality of contact elementsrectilinearly disposed in lines and rows, the elements in each linebeing interconnected and connected to one of said key switches, aplurality of bars each having a plurality of contact elements engagedwith the panel contact elements of one row, said bars beinginterchangeable between rows and being adjustably shiftable along a row,a plurality of sound signal generating units, one for each bar, eachhaving a range of musical tone signals and each having conductors, onefor each tone, energizable to produce respective signals, selectivelyoperable multiple contact stop switch units, the

conductors of said generating units being connected in order to therespective contacts of said stop switch units, and means connectingother contacts of said stop switch units, respectively, to the contactelements of said several bars, said generating units each having asingle musical timbre for the range of tones producible thereby.

18. In an electrical musical instrument, a plurality of playing keyswitches, a connection panel having a plurality of contact elementsrectilinearly disposed in lines and rows, the elements in each linebeing interconnected and connected to one of said key switches, aplurality of bars each having a plurality of contact elements engagedwith the panel contact elements of one row, said bars beinginterchangeable between rows and being adjustably shiftable along a row,a plurality of sound signal generating units, one for each bar, eachhaving a range of musical tone signals and each having conductors, onefor each tone, energizable to produce respective signals, selectivelyoperable multiple contact stop switch units, the

conductors of said generating units being connected in order to therespective contacts of said stop switch units, and means connectingother contacts of said stop switch units, respectively, to the contactelements of sa d several bars, said stop switch units being of a numbercorresponding to more than the number of generating units, and beingconnected for different registries of said key switches with the tonesof said several generating units as well as for nominal registry.

19. In an electrical musical instrument comprising a selectivelyoperable keyboard, a pickup, and a speaker energized by said pick-up, amovable sound track-carrying member having a plurality of tracksthereon, said pickup being associated operably with said tracks, meansresponsive to key operation to energize said pickup for signalproduction resulting from key operation, said plurality of tracks beingarranged in a sequence of groups, each group containing tracks having 15octave. intervals therebetween, and said groups havingfifth'intervalstherebetween.

20. In an electrical musical instrument comprising-a selectivelyoperable. keyboard, a pickup, and a speaker energized by said pickup, amovable sound track-carrying member having a plurality of tracksthereon, said pickup being associated operably with said tracks, meansresponsive to key operation to energize said pickup forxsignalproduction resulting from key operation, there being} fifth intervalsbetween certain individual adjacenttracks of said plurality.

21. In an electrical musical instrument comprising a selectivelyoperable keyboard, a pickup,

a speaker energized by said pickup, a movable sound track-carryingmember having a plurality of tracks thereon, said pickup beingassociated opera-bly with said tracks, means responsive tokey operationto energizesaid pickup for sig- 16 nal production resulting from keyoperation, there being octave intervals between certain in dividualadjacent tracks of said plurality.

' MAURICE GRUDIN.

REFERENCES CITED The following references are of record: in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 978,722 Fajen e Dec, 13,19101,218,824 Severy Mar. 6,1917 1,848,222 Potter i Mar. 8, 1932 1,941,870Severy Jan.. 2, 1934 1,956,350 Hammond Apr. 24, 1934 2,164,809 FisherJuly 4, 1939' 2,169,842 Kannenberg Aug. 15,1939 2,484,881

SuSChi Oct. 18,, 19.49.

